Pararetroviruses, taxon Caulimoviridae, are typical of retroelements with reverse transcriptase and share a common origin with retroviruses and LTR retrotransposons, presumably dating back 1.6 billion years and illustrating the transition from an RNA to a DNA world. After transcription of the viral genome in the host nucleus, viral DNA synthesis occurs in the cytoplasm on the generated terminally redundant RNA including inter- and intra-molecule recombination steps rather than relying on nuclear DNA replication. RNA recombination events between an ancestral genomic retroelement with exogenous RNA viruses were seminal in pararetrovirus evolution resulting in horizontal transmission and episomal replication. Instead of active integration, pararetroviruses use the host DNA repair machinery to prevail in genomes of angiosperms, gymnosperms and ferns. Pararetrovirus integration – leading to Endogenous ParaRetroViruses, EPRVs – by illegitimate recombination can happen if their sequences instead of homologous host genomic sequences on the sister chromatid (during mitosis) or homologous chromosome (during meiosis) are used as template. Multiple layers of RNA interference exist regulating episomal and chromosomal forms of the pararetrovirus. Pararetroviruses have evolved suppressors against this plant defense in the arms race during co-evolution which can result in deregulation of plant genes. Small RNAs serve as signaling molecules for Transcriptional and Post-Transcriptional Gene Silencing (TGS, PTGS) pathways. Different populations of small RNAs comprising 21–24 nt and 18–30 nt in length have been reported for Citrus, Fritillaria, Musa, Petunia, Solanum and Beta. Recombination and RNA interference are driving forces for evolution and regulation of EPRVs.

No abstract

Many attempts have been made to reduce or limit the economic damage caused by the fig mosaic virus to the growth of fig trees and their production from the fruits, in this study the disease in fig seedlings was controlled by aqueous extracts of licorice roots and garlic cloves, salicylic acid. experiments in the greenhouse showed that salicylic acid spraying treatments and aqueous extracts of licorice root and garlic plant cloves individually and twice on intact fig seedlings infected with the fig mosaic virus had a significant effect in reducing the severity of the virus and increasing plant growth indicators such as number of leaves, plant height, leaf content of chlorophyll and elements Nitrogen and phosphorous, and the interaction treatment between licorice extract and garlic cloves extract outperformed in achieving the lowest rate of infection severity, which reached 26.45%, compared to the control treatment, which amounted to 90.36%.

No abstract

Here, we report the coding-complete sequence of Cowpea mild mottle virus (CPMMV; strain Hilla) in cowpea using total transcriptome sequencing (RNA-seq) and bioinformatics analyses. The sequence length was 8,119 bp long and has 6 open reading frames. The genome was phylogenetically close to two isolates collected from Ghana.

Tomato yield and quality in Iraq have been threatened by a variable range of infections caused by tomato yellow leaf curl virus. In previous studies, the TYLCV isolates were characterized using molecular tests for small fragments not the entire length of the virus. As a part of long term study, sample of slightly TYLCV-infected tomato has applied in this study to figure out complete sequence of TYLCV isolate. Three sets of primers that belong to three well-known isolates in Iraq were used in a PCR technique and interestingly the results were negative. A new Iraqi isolate has been characterized as a first novel Iraqi isolate detected ever using next generation (NGS) and bioinformatics techniques. The NGS platform has produced about 78,232,062 paired reads of the TYLCV-infected tomato var. Oula F1. The complete raw reads of the infected variety have been analyzed using RepeatExplorer pipeline and Map to reference. The full sequence of TYLCV was reconstructed and extracted to consist of 2770 nt and then deposited in Genbank under accession number MT583814. Copy numbers and genome proportion of this sequence have been calculated that were 3523 and 0,086% respectively. Phylogenetic analyses of full nucleotide sequences confirmed close relationship to Iranian isolate (TYLCV-Kahnooj) than other published viruses. Additionally, a and β DNA satellites have not discovered in the TYLCV-infected sample.